ELI5: Explain Like I'm 5

Biological agent

A biological agent is anything that is alive and can cause harm or disease. Examples of this include bacteria, viruses, insects, and fungi. These agents can cause illnesses and can be spread from one person to another or from an animal, such as an insect, to a person. To protect people, doctors and scientists work together to monitor for dangerous biological agents and find ways to prevent them from causing harm.